Interference of Red Rice (Oryza sativa) with Rice (O. sativa)

Abstract

Red rice (Oryza sativaL. ♯ ORYSA) densities of 5, 108, and 215 plants/m2reduced grain yield of commercial rice (Oryza sativaL.) 22, 77, and 82%, respectively. At a cultivated rice density of 195 plants/m2, red rice at 5, 108, and 215 plants/m2reduced straw dry weight of cultivated rice 18, 66, and 68%, respectively. At a red rice density of 5 plants/m2, reduction in number of cultivated rice grains per panicle ranged from 8 to 18%, whereas densities of 108 and 215 plants/m2reduced grains per panicle 56 to 70%. Red rice grain yield was 24 to 33% lower in ‘Mars' rice than in ‘Lebonnet’. Mars, a medium-grain cultivar that matures in 138 days, competed better with red rice than Lebonnet, a long-grain cultivar that matures in 126 days.